Key matrix for a handset



FIG. 1 is an upper perspective front view of the new design applied to the key matrix of a handset;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a bottom view thereof; and,

FIG. 5 is a left side view thereof.

The portion of the handset shown in broken lines is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for key matrix for a handset, as shown. 